1. Field of the Invention
This invention generally relates to stringed instruments, and particularly to large-size stringed instruments such as contrabasses in which intermediate portions of strings are supported by bridges having height-adjustment functions.
2. Description of the Related Art
Generally, stringed instruments have bridges for supporting strings under tension. Particularly, large-size stringed instruments such as contrabasses use bridges that stand on bellies of the instruments to support intermediate portions of strings under tension. Those bridges are made by pieces of wood, namely, wood plates which are normally made of hard wood materials such as maple and which are gradually reduced in thickness toward tip ends. Each of those bridges has four grooves at an upper portion thereof, so that four strings are respectively engaged with the four grooves of the bridge. In addition, a lower end portion of the bridge is forked to form two leg portions. Normally, there are provided two types of the bridges, namely, a first type of the bridge that is attached to the belly of the stringed instrument in a height-adjustable manner and a second type of the bridge that does not have a height-adjustment function. FIG. 4 shows an example of the conventional bridge that is merely attached to the belly of the stringed instrument without having a height-adjustment function. In FIG. 4, a reference numeral 1 designates a bridge, 2 designates a body (or belly) of a stringed instrument, 3 designates four grooves for supporting four strings 4 respectively, and 5 designates two legs of the bridge 1. FIG. 5 shows an example of the conventional bridge that is attached to the belly of the stringed instrument in a height-adjustable manner. In addition to the aforementioned elements shown in FIG. 4, the bridge shown in FIG. 5 provides a pair of heightadjustment members 6 for supporting the two legs 5 respectively. Each of the height-adjustment members 6 contains an internally-threaded member (or nut) 7, a screw rod 8, a foot 9 and an adjustment screw 10. Herein, the screw rod 8 engages with the internally-threaded member 7 which is buried in the foot 9 being attached on the stringed instrument 2, and the adjustment screw 10 engages with an intermediate portion of the screw rod 8 whose upper portion is inserted into a hole 11 which is formed inside of the leg 5 to communicate with its lower surface. The adjustment screw 10 has a disk-like shape whose upper surface supports the lower surface of the leg 5. When being rotated, the adjustment screw 10 moves up or down along the screw rod 8, so that a height of the bridge 1 is being adjusted. Lifting up the bridge 1, the upper portion of the screw rod 8 can be easily extracted from the hole 11 of the leg 5. Hence, it is possible to easily remove the bridge 1 from the height-adjustment members 6 that are fixedly attached to the belly of the stringed instrument 2. In other words, if a human operator (or player) holds the stringed instrument 2 such that the bridge 1 is placed in a downward direction, the bridge 1 is being easily dropped from the height-adjustment members 6 attached to the belly of the stringed instrument 2.
As described above, the bridge shown in FIG. 4 bears a drawback due to lack of the height-adjustment function. It may be possible to compulsorily provide the bridge of FIG. 4 with a height-adjustment function, which is realized by shaving the legs 5 to be shorter. However, once the legs 5 are shaved to be shorter so that a height of the bridge is being reduced, it becomes impossible to increase the height of the bridge. In contrast to the bridge of FIG. 4, the bridge of FIG. 5 has height-adjustment members 6 by which the bridge can be freely adjusted in height. However, the bridge of FIG. 5 bears a problem due to plenty of parts because each leg portion is constructed by five members, namely, the leg 5, internally-threaded member 7, screw rod 8, foot 9 and adjustment screw 10. In addition, the screw rod 8 and adjustment screw 10 are made of metal materials, which may cause a problem in visuality as compared with the xe2x80x9cwoodxe2x80x9d bridge. That is, a player may feel visual wrongness or reluctance in watching those xe2x80x9cmetalxe2x80x9d parts that appear in connection with the xe2x80x9cwoodxe2x80x9d bridge. Further, the bridge of FIG. 5 is constructed such that the upper portion of the screw rod 8 is merely inserted into the hole 11 of the leg 5. So, if the screw rods 8 are removed from the stringed instrument 2, it becomes easy to disassemble the bridge 1 from the height-adjustment members 6. That is, it is difficult for the human operator (or player) to handle the bridge 1 being attached to the stringed instrument 2.
It is an object of the invention to provide a height-adjustable bridge assembly for use in a stringed instrument by a reduced number of parts including metal parts which are arranged inconspicuously inside of wood materials to provide least resistance in visuality.
A stringed instrument such as a contrabass uses a height-adjustable bridge assembly for supporting strings under tension with a desired height, which is manually adjusted by a human operator. The bridge assembly of this invention is mainly constructed by a bridge whose lower end portion is forked to form a pair of legs and a pair of height-adjustment members, each of which is constructed by a screw rod and a foot. The legs of the bridge are respectively assembled together with the height-adjustment members being held inside of a hollow which is formed at a prescribed position and elongated in a direction roughly perpendicular to the strings being stretched on a belly of the stringed instrument. Herein, each leg has a hole formed with an internal thread which engages with an upper portion of the screw rod whose lower portion is buried in the foot which is held inside of the hollow in a free rotation manner. Hence, it is possible for the human operator to manually adjust a height of the bridge by merely rotating the feet within the hollow on the stringed instrument while temporarily loosening the strings. This guarantees easy manual operations for the human operator in adjustment of the height of the bridge and adjustment of stretching the strings on the stringed instrument.
Because of elimination of adjustment screws, it is possible to construct the bridge assembly with a reduced number of parts as compared with conventional ones. In addition, metal parts (i.e., screw rods) are completely hidden inside of wood parts of the bridge assembly to provide least resistance in visuality.